In the Blu-ray® specification, 3D stream files can be played by both 2D players and 3D players. A 3D player will read the entire 3D stream, while a 2D player reads only the 2D portion of the stream, which includes 2D video as well as audio streams.
The above specification defines two types of 3D streams: 1TS and 2TS. The 1TS stream includes both base view video and dependent view video in a single transport stream. This transport stream is maximum bit rate limited to 48 Mbps, so in general this type does not have a high enough bit rate to multiplex high quality 3D video with multiple high-quality audio streams. The 2TS stream files have a maximum total bit rate for the base and dependent transport streams of 64 Mbps and thus has enough bit rate to carry high-quality 3D video and audio.
The 2TS stream includes base view video and audio streams in one transport stream file, and includes dependent view video in another transport stream. As a result, the base view video is often larger in extent, and often has a higher bit rate. In fact, the dependent view bit rate may approach zero if the view varies very little from the base view, because of the way MVC encodes data.
The 2TS stream files are interleaved, and as noted incorporate base view blocks and dependent view blocks. Such stream files are stored as one hybrid file termed an SSIF file in the Blu-ray® specification, where SSIF refers to a stereoscopic interleaved file.
In more detail, in one implementation, and referring to prior art FIG. 1, an architecture 10 includes a 2TS 3D stream file 16 that includes a base view transport stream (TS) file 12 and a dependent view TS file 14. The 3D stream file 16 is broken into a set of base view blocks 22j and a set of dependent view blocks 18i. Both are employed for 3D playback, e.g., base view for left eye and dependent view for right eye, or vice-versa, and just the base view 22j is used for 2D playback.
When a player performs a drive seek to read the blocks of the AV (audiovisual) stream, the player needs to buffer enough AV stream data to a read buffer to continue smooth playback, at least until the drive starts reading new AV stream data after a jump.
Two situations require special handling: playback over an optical media layer jump and play back in a multi-story branching situation (FIGS. 2-4). Referring first to the layer break jump illustrated by the sequence 20 in prior art FIG. 2, a 3D stream file 24 is multiplexed into a base view and dependent view of the 3D stream, and a number of base view blocks 26i and dependent view blocks 28j are defined. A layer break 32k is established where desired, and the same may be estimated using time codes or file sizes. The layer break 32, which usually constitutes a long jump, is typically set at the block boundary closest to the requested timecode or file size. In many cases, current authoring systems employ “parameters-A” to determine the jump point. These may include AV stream maximum bit rate, drive jump performance, and jump distance, or a sub combination of these. In many cases, the target jump point is determined by stream file size, then evaluated based on the parameters-A.
The Blu-ray® specification then sets a number of conditions that must be established for seamless playback, and these are checked, for a proposed jump point, in step 34. If seamless playback does not occur, the layer break is moved, i.e., a different layer break point is attempted. If seamless playback is achieved, a layer size check 36 is performed to ensure the layer size does not exceed the maximum size set for the medium and further such that the first layer size is larger than or equal to the second layer size as required in the Blu-ray® specification. Finally, a file system image is created, e.g., a master disc is created in step 38.
FIG. 3 illustrates a prior art method 30 for a medium including 2D multi-story branching. The 2D stream is shown with a multi-story playback path set up including chapters A (42), B (44/46), and C (48), where B has two alternative branches B1 (44) and B2 (46). In the case where the size of B1 or B2 is larger than a maximum jump distance, B1 and B2 are interleaved to keep the jump distance less than the maximum. For example B1 (44) and B2 (46) may be further broken up into (for B1) B1[1]=44(1) and B1[2]=44(2); and (for B2) B2[1]=46(1) and B2[2]=46(2). That is, the components of B1 and B2 are interleaved such that the maximum jump distance is less than a predetermined maximum, e.g., 640,000 sectors or 1.28 Gb for a current Blu-ray® disc to cap the drive seek time. Sample playback paths are illustrated, both for branch A-B2-C (bottom path) and for branch A-B1-C (top path).
As in FIG. 2, a seamless playback check is performed in step 52. If seamless playback does not occur, the interleaving is performed again in a different way. As above, a layer size check 54 is performed to ensure the layer size does not exceed the maximum size set for the medium and that the first layer size is larger than or equal to the second layer size as required in the Blu-ray® specification. Finally, a file system image is created, e.g., a master disc is created in step 56.
FIG. 4 illustrates a prior art method 40 for a medium including 3D multi-story branching. The 3D stream is shown as set up with a multi-story playback path having chapters A (62), B (64/66), and C (68), where B has two alternative branches B1 (64) and B2 (66). All of the chapters or 3D stream files are shown divided into base and dependent view blocks 62i, 62j, 64i, 64j, 66i, 66j, 68i, and 68j. Where B1 or B2 are larger than a maximum jump distance, the two may be interleaved to keep the jump distance less than a maximum. Again, this maximum jump distance is currently about 1.28 GB. As an example of interleaving, B1 (64) and B2 (66) are further broken up into (for B1) B1[1] and B1[2]; and (for B2) B2[1] and B2[2]. The interleaving is such that the maximum jump distance is less than the predetermined maximum. Sample playback paths are illustrated, both for branch A-B2-C (bottom path) and for branch A-B1-C (top path).
Again, a seamless playback check is performed in step 72. Following the seamless playback check, a layer size check 74 is performed to ensure the layer size does not exceed the maximum size set for the medium. Finally, a file system image is created, e.g., a master disc is created in step 76.